Potato cultivar ‘Shelford’

ABSTRACT

A potato cultivar designated ‘Shelford’ is disclosed. The invention relates to the tubers of potato cultivar ‘Shelford’, to the seeds of potato cultivar ‘Shelford’, to the plants of potato ‘Shelford’, to the plant parts of potato cultivar ‘Shelford’ and to methods for producing a potato plant produced by crossing potato cultivar ‘Shelford’ with itself or with another potato variety. The invention also relates to methods for producing a potato plant containing in its genetic material one or more transgenes and to the transgenic potato plants and plant parts produced by those methods. This invention also relates to potato cultivars or breeding cultivars and plant parts derived from potato variety ‘Shelford’, to methods for producing other potato cultivars, lines or plant parts derived from potato cultivar ‘Shelford’ and to the potato plants, varieties, and their parts derived from use of those methods. The invention further relates to hybrid potato tubers, seeds, plants and plant parts produced by crossing potato cultivar ‘Shelford’ with another potato cultivar.

BACKGROUND OF THE INVENTION

The present invention relates to a novel potato variety designated‘Shelford’ and to the tubers, plants, plant parts, tissue culture andseeds produced by that potato variety. All publications cited in thisapplication are herein incorporated by reference.

The potato is the world's fourth most important food crop and by far themost important vegetable. Potatoes are currently grown commercially innearly every state of the United States. Annual potato productionexceeds 18 million tons in the United States and 300 million tonsworldwide. The popularity of the potato derives mainly from itsversatility and nutritional value. Potatoes can be used fresh, frozen ordried, or can be processed into flour, starch or alcohol. They containcomplex carbohydrates and are rich in calcium, niacin and vitamin C.

To keep the potato industry growing to meet the needs of the consumingpublic, substantial research and development efforts are devoted to themodernization of planting and harvesting of fields and processing ofpotatoes, and to the development of economically advantageous potatovarieties. Through crossbreeding of potatoes, researchers hope to obtainpotatoes with the desirable characteristics of good processability, highsolids content, high yield, resistance to diseases and pests andadaptability to various growing areas and conditions.

The U.S. acreage planted in potatoes has declined since the 1960s and1970s, and this decline, coupled with increasing consumption, must beoffset by higher useable yields. In some areas, diseases and pestsdamage crops despite the use of herbicides and pesticides. The problemof the golden nematode in the United States, presently endemic toportions of New York State, is one example of the destruction tosusceptible potato varieties. Potato varieties with high yields, diseaseresistance and adaptability to new environments can eliminate manyproblems for the potato grower and provide more plentiful and economicalproducts to the consumers.

For the potato chip processing industry, potatoes having high solidscontent, good shipping qualities and good finished chip color canincrease production volumes and efficiencies and product acceptability.Potato varieties which yield low-solids tubers result in unnecessaryenergy usage during the frying process. Moreover, as solids contentincreases, the oil content of fried products decreases, which is afavorable improvement. Potato varieties in the warm southern tier ofstates are most in need of solids improvement overall, while thosevarieties grown and stored in the colder northern tier of states aremost in need of the ability to recondition after cool or cold storage toincrease their value for use in the potato chip industry. Reconditioningis necessary to elevate the temperature of the potatoes after coldstorage and before further processing.

The research leading to potato varieties which combine the advantageouscharacteristics referred to above is largely empirical. This researchrequires large investments of time, labor, and money. The development ofa potato cultivar can often take up to eight years or more fromgreenhouse to commercial usage. Breeding begins with careful selectionof superior parents to incorporate the most important characteristicsinto the progeny. Since all desired traits usually do not appear withjust one cross, breeding must be cumulative.

Present breeding techniques continue with the controlled pollination ofparental clones. Typically, pollen is collected in gelatin capsules forlater use in pollinating the female parents. Hybrid seeds are sown ingreenhouses and tubers are harvested and retained from thousands ofindividual seedlings. The next year one to four tubers from eachresulting seedling are planted in the field, where extreme caution isexercised to avoid the spread of virus and diseases. From thisfirst-year seedling crop, several “seed” tubers from each hybridindividual which survived the selection process are retained for thenext year's planting. After the second year, samples are taken fordensity measurements and fry tests to determine the suitability of thetubers for commercial usage. Plants which have survived the selectionprocess to this point are then planted at an expanded volume the thirdyear for a more comprehensive series of fry tests and densitydeterminations. At the fourth-year stage of development, survivingselections are subjected to field trials in several states to determinetheir adaptability to different growing conditions. Eventually, thevarieties having superior qualities are transferred to other farms andthe seed increased to commercial scale. Generally, by this time, eightor more years of planting, harvesting and testing have been invested inattempting to develop the new and improved potato cultivars.

Long-term, controlled-environment storage has been a feature of thenorthern, principal producing areas for many years. Potatoes harvestedby October must be kept in good condition for up to eight months intemperatures that may drop to −30 degrees C. at times and with very lowrelative humidity in the outside air. Storages are well insulated, notonly to prevent heat loss but also to prevent condensation on outsidewalls. The circulation of air at the required temperature and humidityis automatically controlled depending on the purpose for which thepotatoes are being stored. Sprout inhibition is now largely carried outin storage as it has been found to be more satisfactory than theapplication of maleic hydrazide (MH30) in the field.

Proper testing of new plants should detect any major faults andestablish the level of superiority or improvement over currentvarieties. In addition to showing superior performance, a new varietymust be compatible with industry standards or create a new market. Theintroduction of a new variety will increase costs of the tuberpropagator, the grower, processor and consumer for special advertisingand marketing, altered tuber propagation and new product utilization.The testing preceding release of a new variety should take intoconsideration research and development costs as well as technicalsuperiority of the final variety. Once the varieties that give the bestperformance have been identified, the tuber can be propagatedindefinitely as long as the homogeneity of the variety parent ismaintained.

For tuber propagated varieties, it must be feasible to produce, storeand process potatoes easily and economically. Thus, there is acontinuing need to develop potato cultivars which provide goodprocessability out of storage, with minimal bruising, for manufacturersof potato chips and other potato products and to combine thischaracteristic with the properties of disease and pest resistance. Thepresent invention addresses this need by providing the new variety asdescribed herein.

The foregoing examples of the related art and limitations relatedtherewith are intended to be illustrative and not exclusive. Otherlimitations of the related art will become apparent to those of skill inthe art upon a reading of the specification.

SUMMARY OF THE INVENTION

The following embodiments and aspects thereof are described inconjunction with systems, tools and methods which are meant to beexemplary, not limiting in scope. In various embodiments, one or more ofthe above-described problems have been reduced or eliminated, whileother embodiments are directed to other improvements.

According to the invention, there is provided a new potato cultivar ofthe genus and species Solanum tuberosum L. designated ‘Shelford’. Thisinvention thus relates to the tubers of potato cultivar ‘Shelford’, tothe plants of potato cultivar ‘Shelford’, to the seeds of potatocultivar ‘Shelford’, and to methods for producing a potato plantproduced by selfing potato cultivar ‘Shelford’ or by crossing potatocultivar ‘Shelford’ with another potato cultivar, and the creation ofvariants by mutagenesis or transformation of potato cultivar ‘Shelford’.

Thus, any such methods using the cultivar ‘Shelford’ are part of thisinvention: selfing, backcrosses, hybrid production, crosses topopulations, and the like. All plants produced using potato cultivar‘Shelford’ as at least one parent are within the scope of thisinvention. Advantageously, the potato cultivar could be used in crosseswith other, different, potato plants to produce first generation (F₁)potato hybrid tubers, seeds and plants with superior characteristics.

In another aspect, the present invention provides for single or multiplegene converted plants of potato cultivar ‘Shelford’. The transferredgene(s) may preferably be a dominant or recessive allele(s). Preferably,the transferred gene(s) will confer such traits as herbicide resistance,insect resistance, resistance for bacterial, fungal, or viral disease,male fertility, male sterility, enhanced nutritional quality,uniformity, and increase in concentration of starch and othercarbohydrates, decrease in tendency to bruise and decrease in the rateof conversion of starch to sugars. The gene(s) may be a naturallyoccurring potato gene or a transgene introduced through geneticengineering techniques, backcrossing or mutation.

In another aspect, the present invention provides regenerable cells foruse in tissue culture of potato cultivar ‘Shelford’. The tissue culturewill preferably be capable of regenerating plants having all thephysiological and morphological characteristics of the foregoing potatoplant, and of regenerating plants having substantially the same genotypeas the foregoing potato plant. Preferably, the regenerable cells in suchtissue cultures will be embryos, protoplasts, meristematic cells,callus, pollen, leaves, anthers, pistils, cotyledons, hypocotyl, roots,root tips, flowers, seeds, petioles, tubers, eyes or stems. Stillfurther, the present invention provides potato plants regenerated fromtissue cultures of the invention.

In addition to the exemplary aspects and embodiments described above,further aspects and embodiments will become apparent by study of thefollowing descriptions.

DEFINITIONS

In the description and tables which follow, a number of terms are used.In order to provide a clear and consistent understanding of thespecification and claims, including the scope to be given such terms,the following definitions are provided:

Allele. An allele is any of one or more alternative forms of a genewhich relate to one trait or characteristic. In a diploid cell ororganism, the two alleles of a given gene occupy corresponding loci on apair of homologous chromosomes.

Backcrossing. Backcrossing is a process in which a breeder repeatedlycrosses hybrid progeny back to one of the parents, for example, a firstgeneration hybrid F₁ with one of the parental genotypes of the F₁hybrid.

Bacterial Ring Rot. Bacterial ring rot is a disease caused by thebacterium Clavibacter michiganense ssp. Bacterial ring rot derives itsname from a characteristic breakdown of the vascular ring within thetuber. This ring often appears as a creamy-yellow to light-brown, cheesyrot. On the outer surface of the potato, severely diseased tubers mayshow slightly sunken, dry and cracked areas. Symptoms of bacterial ringrot in the vascular tissue of infected tubers can be less obvious thandescribed above, appearing as only a broken, sporadically appearing darkline or as a continuous, yellowish discoloration.

Black spot. Black spots found in bruised tuber tissue are a result of apigment called melanin that is produced following the injury of cellsand gives tissue a brown, gray or black appearance. Melanin is formedwhen phenol substrates and an appropriate enzyme come in contact witheach other as a result of cellular damage. The damage does not requirebroken cells. However, mixing of the substrate and enzyme must occur,usually when the tissue is impacted. Black spots occur primarily in theperimedullary tissue just beneath the vascular ring, but may be largeenough to include a portion of the cortical tissue.

Cotyledon. A cotyledon is a type of seed leaf. The cotyledon containsthe food storage tissues of the seed.

Embryo. The embryo is the small plant contained within a mature seed.

FL Solids. FL solids refer to the percentage of solid matter containedin tubers and is calculated by the formula FL Solids=(178.093×Specificgravity of sample)−175.560.

Gene. As used herein, “gene” refers to a segment of nucleic acid. A genecan be introduced into a genome of a species, whether from a differentspecies or from the same species, using transformation or variousbreeding methods.

Gene Converted (Conversion). Gene converted (conversion) plant refers toplants which are developed by a plant breeding technique calledbackcrossing wherein essentially all of the desired morphological andphysiological characteristics of a variety are recovered in addition tothe one or more genes transferred into the variety via the backcrossingtechnique, via genetic engineering or via mutation. One or more loci mayalso be transferred.

Hypocotyl. A hypocotyl is the portion of an embryo or seedling betweenthe cotyledons and the root. Therefore, it can be considered atransition zone between shoot and root.

Locus. A locus confers one or more traits such as, for example, malesterility, herbicide tolerance, insect resistance, disease resistance,waxy starch, modified fatty acid metabolism, modified phytic acidmetabolism, modified carbohydrate metabolism, and modified proteinmetabolism. The trait may be, for example, conferred by a naturallyoccurring gene introduced into the genome of the variety bybackcrossing, a natural or induced mutation, or a transgene introducedthrough genetic transformation techniques. A locus may comprise one ormore alleles integrated at a single chromosomal location.

Marketable Yield. Marketable yield is the weight of all tubers harvestedthat are between 2 and 4 inches in diameter. Marketable yield ismeasured in cwt (hundred weight) where cwt=100 pounds.

Plant. As used herein, the term “plant” includes reference to animmature or mature whole plant, including a plant from which seed,grain, or anthers have been removed. Seed or embryo that will producethe plant is also considered to be the plant.

Plant Parts. As used herein, the term “plant parts” (or a potato plant,or a part thereof) includes, but is not limited to, protoplast, leaf,stem, root, root tip, anther, pistil, seed, embryo, pollen, ovule,cotyledon, hypocotyl, flower, tuber, eye, tissue, petiole, cell andmeristematic cell, and the like.

Progeny. As used herein, includes an F₁ potato plant produced from thecross of two potato plants where at least one plant includes potatocultivar ‘Shelford’ and progeny further includes, but is not limited to,subsequent F₂, F₃, F₄, F₅, F₆, F₇, F₈, F₉, and F₁₀ generational crosseswith the recurrent parental line.

Quantitative Trait Loci (QTL). Quantitative trait loci (QTL) refer togenetic loci that control to some degree numerically representabletraits that are usually continuously distributed.

Regeneration. Regeneration refers to the development of a plant fromtissue culture.

Solid/Acre. Solid/acre refers to marketable yield (in pounds)×FL Solids.

Total Yield. Total yield refers to the total weight of all harvestedtubers.

Vine Maturity. Vine maturity refers to a plant's ability to continue toutilize carbohydrates and photosynthesize. Vine maturity is scored on ascale of 1 to 5 where 1=dead vines and 5=vines green, still flowering.

DETAILED DESCRIPTION OF THE INVENTION

A potato cultivar of the present invention, designated ‘Shelford’, hasbeen obtained by selectively crossbreeding parental clones throughseveral generations. The parents of ‘Shelford’ are ‘FL 1625’ and‘Hermes’. Shelford was bred in a research facility near Rhinelander,Wis., USA and was subsequently tested in the UK.

Potato cultivar ‘Shelford’ has round-oval tubers with yellow flesh andshallow-medium to medium eye depth.

Potato cultivar ‘Shelford’ has been uniform and stable since its originas a single plant in 1996. No variants of potato cultivar ‘Shelford’have been observed.

Potato variety ‘Shelford’ has the following morphologic and othercharacteristics (based on data collected in the UK).

TABLE 1 VARIETY DESCRIPTION INFORMATION Classification: Solanumtuberosum L. Plant: Maturity: Early maincrop Light Sprout: Size: MediumShape: Ovoid Color of base: Pink Intensity of pigment on base: Faint tomedium Pubescence: Moderate Size of tip: Medium Habit of tip: MediumIntensity of color at tip: Faint Pubescence of tip: Medium Number ofroot tips: Medium to many Protrusion of lenticels: Medium Length oflateral shoots: Short to medium Stem: Height: Medium Type: Leaf typeHabit: Semi-erect Thickness: Medium Color: Absent to faint (local) Leaf:Size: Medium Openness: Intermediate Primary Leaflet: Color: Light to midPigment on petiolule: Faint lines/apical leaflets Size: Medium Shape:Medium Fusion of terminal: Rare Waved margins: None/very weak Veindepth: Medium Pigment at apical rosette: Absent Texture: MediumSecondary Leaflet: Frequency: Medium Presence on terminal leaflet:Frequent Presence on lateral leaflet: Medium Size: Medium Inflorescence:Frequency of flowers: Absent/rare Fruits frequency: Absent Tuber: Shape:Round-oval Depth of eyes: Shallow medium to medium Smoothness of skin:Smooth Color of skin: White Color of base of eyes: Yellow Color offlesh: Yellow Pigment development on skin: Absent/very weak Diseasereactions: (On a scale of 1 to 9, where 1 is very susceptible and 9 ishighly resistant) Late blight on foliage (Phytophthora infestans): 4,moderately susceptible Late blight on tubers (Phytophthora infestans):2, susceptible Dry rot (Fusarium coeruleum): 5, moderately resistant Dryrot (Fusarium sulphureum): 1, very susceptible Common scab (Streptomycesscabiei): 3, susceptible to moderately susceptible Powdery scab(Spongospora): 5, moderately resistant Blackleg (Pectobacteriumatrosepticum): 7, resistant Potato Cyst Nematode (Globodera pallida Pa2/3, 1): 2, susceptible Potato Cyst Nematode (Globodera rostochiensisRo1): 2, susceptible Potato Leafroll Virus: 7, resistant Potato VirusYo: 7, resistant

FURTHER EMBODIMENTS OF THE INVENTION

With the advent of molecular biological techniques that have allowed theisolation and characterization of genes that encode specific proteinproducts, scientists in the field of plant biology developed a stronginterest in engineering the genome of plants to contain and expressforeign genes, or additional, or modified versions of native, orendogenous, genes (perhaps driven by different promoters) in order toalter the traits of a plant in a specific manner. Such foreignadditional and/or modified genes are referred to herein collectively as“transgenes”. Over the last fifteen to twenty years several methods forproducing transgenic plants have been developed, and the presentinvention, in particular embodiments, also relates to transformedversions of the claimed variety or line.

Plant transformation involves the construction of an expression vectorwhich will function in plant cells. Such a vector comprises DNAcomprising a gene under control of, or operatively linked to, aregulatory element (for example, a promoter). The expression vector maycontain one or more such operably linked gene/regulatory elementcombinations. The vector(s) may be in the form of a plasmid, and can beused alone or in combination with other plasmids, to provide transformedpotato plants, using transformation methods as described below toincorporate transgenes into the genetic material of the potato plant(s).

Expression Vectors for Potato Transformation: Marker Genes

Expression vectors include at least one genetic marker, operably linkedto a regulatory element (a promoter, for example) that allowstransformed cells containing the marker to be either recovered bynegative selection, i.e., inhibiting growth of cells that do not containthe selectable marker gene, or by positive selection, i.e., screeningfor the product encoded by the genetic marker. Many commonly usedselectable marker genes for plant transformation are well known in thetransformation arts, and include, for example, genes that code forenzymes that metabolically detoxify a selective chemical agent which maybe an antibiotic or an herbicide, or genes that encode an altered targetwhich is insensitive to the inhibitor. A few positive selection methodsare also known in the art.

One commonly used selectable marker gene for plant transformation is theneomycin phosphotransferase II (nptII) gene which, when under thecontrol of plant regulatory signals, confers resistance to kanamycin.Fraley et al., Proc. Natl. Acad. Sci. U.S.A., 80:4803 (1983). Anothercommonly used selectable marker gene is the hygromycinphosphotransferase gene which confers resistance to the antibiotichygromycin. Vanden Elzen et al., Plant Mol. Biol., 5:299 (1985).

Additional selectable marker genes of bacterial origin that conferresistance to antibiotics include gentamycin acetyl transferase,streptomycin phosphotransferase and aminoglycoside-3′-adenyltransferase, the bleomycin resistance determinant. Hayford et al., PlantPhysiol. 86:1216 (1988), Jones et al., Mol. Gen. Genet., 210:86 (1987),Svab et al., Plant Mol. Biol. 14:197 (1990) Hille et al., Plant Mol.Biol. 7:171 (1986). Other selectable marker genes confer resistance toherbicides such as glyphosate, glufosinate or bromoxynil. Comai et al.,Nature 317:741-744 (1985), Gordon-Kamm et al., Plant Cell 2:603-618(1990) and Stalker et al., Science 242:419-423 (1988).

Selectable marker genes for plant transformation not of bacterial origininclude, for example, mouse dihydrofolate reductase, plant5-enolpyruvylshikimate-3-phosphate synthase and plant acetolactatesynthase. Eichholtz et al., Somatic Cell Mol. Genet. 13:67 (1987), Shahet al., Science 233:478 (1986), Charest et al., Plant Cell Rep. 8:643(1990).

Another class of marker genes for plant transformation requiresscreening of presumptively transformed plant cells rather than directgenetic selection of transformed cells for resistance to a toxicsubstance such as an antibiotic. These genes are particularly useful toquantify or visualize the spatial pattern of expression of a gene inspecific tissues and are frequently referred to as reporter genesbecause they can be fused to a gene or gene regulatory sequence for theinvestigation of gene expression. Commonly used genes for screeningpresumptively transformed cells include β-glucuronidase (GUS),β-galactosidase, luciferase and chloramphenicol acetyltransferase.Jefferson, R. A., Plant Mol. Biol. Rep. 5:387 (1987), Teeri et al., EMBOJ. 8:343 (1989), Koncz et al., Proc. Natl. Acad. Sci. USA 84:131 (1987),DeBlock et al., EMBO J. 3:1681 (1984).

In vivo methods for visualizing GUS activity that do not requiredestruction of plant tissue are available. Molecular Probes publication2908, IMAGENE GREEN, p. 1-4 (1993) and Naleway et al., J. Cell Biol.115:151a (1991). However, these in vivo methods for visualizing GUSactivity have not proven useful for recovery of transformed cellsbecause of low sensitivity, high fluorescent backgrounds and limitationsassociated with the use of luciferase genes as selectable markers.

More recently, a gene encoding Green Fluorescent Protein (GFP) has beenutilized as a marker for gene expression in prokaryotic and eukaryoticcells. Chalfie et al., Science 263:802 (1994). GFP and mutants of GFPmay be used as screenable markers.

Expression Vectors for Potato Transformation: Promoters

Genes included in expression vectors must be driven by a nucleotidesequence comprising a regulatory element, for example, a promoter.Several types of promoters are well known in the transformation arts asare other regulatory elements that can be used alone or in combinationwith promoters.

As used herein, “promoter” includes reference to a region of DNAupstream from the start of transcription and involved in recognition andbinding of RNA polymerase and other proteins to initiate transcription.A “plant promoter” is a promoter capable of initiating transcription inplant cells. Examples of promoters under developmental control includepromoters that preferentially initiate transcription in certain tissues,such as leaves, roots, seeds, fibers, xylem vessels, tracheids, orsclerenchyma. Such promoters are referred to as “tissue-preferred”.Promoters that initiate transcription only in a certain tissue arereferred to as “tissue-specific”. A “cell-type” specific promoterprimarily drives expression in certain cell types in one or more organs,for example, vascular cells in roots or leaves. An “inducible” promoteris a promoter which is under environmental control. Examples ofenvironmental conditions that may effect transcription by induciblepromoters include anaerobic conditions or the presence of light.Tissue-specific, tissue-preferred, cell type specific, and induciblepromoters constitute the class of “non-constitutive” promoters. A“constitutive” promoter is a promoter that is active under mostenvironmental conditions.

A. Inducible Promoters

An inducible promoter is operably linked to a gene for expression inpotato. Optionally, the inducible promoter is operably linked to anucleotide sequence encoding a signal sequence which is operably linkedto a gene for expression in potato. With an inducible promoter the rateof transcription increases in response to an inducing agent.

Any inducible promoter can be used in the instant invention. See Ward etal., Plant Mol. Biol. 22:361-366 (1993). Exemplary inducible promotersinclude, but are not limited to, that from the ACEI system whichresponds to copper (Mett et al., PNAS 90:4567-4571 (1993)); In2 genefrom maize which responds to benzenesulfonamide herbicide safeners(Hershey et al., Mol. Gen Genetics 227:229-237 (1991) and Gatz et al.,Mol. Gen. Genetics 243:32-38 (1994)) or Tet repressor from Tn10 (Gatz etal., Mol. Gen. Genetics 227:229-237 (1991)). A particularly preferredinducible promoter is a promoter that responds to an inducing agent towhich plants do not normally respond. An exemplary inducible promoter isthe inducible promoter from a steroid hormone gene, the transcriptionalactivity of which is induced by a glucocorticosteroid hormone. Schena etal., Proc. Natl. Acad. Sci. USA 88:0421 (1991).

B. Constitutive Promoters

A constitutive promoter is operably linked to a gene for expression inpotato or the constitutive promoter is operably linked to a nucleotidesequence encoding a signal sequence which is operably linked to a genefor expression in potato.

Many different constitutive promoters can be utilized in the instantinvention. Exemplary constitutive promoters include, but are not limitedto, the promoters from plant viruses such as the 35S promoter from CaMV(Odell et al., Nature 313:810-812 (1985)) and the promoters from suchgenes as rice actin (McElroy et al., Plant Cell 2: 163-171 (1990));ubiquitin (Christensen et al., Plant Mol. Biol. 12:619-632 (1989) andChristensen et al., Plant Mol. Biol. 18:675-689 (1992)); pEMU (Last etal., Theor. Appl. Genet. 81:581-588 (1991)); MAS (Velten et al., EMBO J.3:2723-2730 (1984)) and maize H3 histone (Lepetit et al., Mol. Gen.Genetics 231:276-285 (1992) and Atanassova et al., Plant Journal 2 (3):291-300 (1992)).

The ALS promoter, Xbal/Ncol fragment 5′ to the Brassica napus ALS3structural gene (or a nucleotide sequence similarity to said Xbal/Ncolfragment), represents a particularly useful constitutive promoter. SeePCT application WO 96/30530.

C. Tissue-Specific or Tissue-Preferred Promoters

A tissue-specific promoter is operably linked to a gene for expressionin potato. Optionally, the tissue-specific promoter is operably linkedto a nucleotide sequence encoding a signal sequence which is operablylinked to a gene for expression in potato. Plants transformed with agene of interest operably linked to a tissue-specific promoter producethe protein product of the transgene exclusively, or preferentially, ina specific tissue.

Any tissue-specific or tissue-preferred promoter can be utilized in theinstant invention. Exemplary tissue-specific or tissue-preferredpromoters include, but are not limited to, a root-preferredpromoter—such as that from the phaseolin gene (Murai et al., Science23:476-482 (1983) and Sengupta-Gopalan et al., Proc. Natl. Acad. Sci.USA 82:3320-3324 (1985)); a leaf-specific and light-induced promotersuch as that from cab or rubisco (Simpson et al., EMBO J.4(11):2723-2729 (1985) and Timko et al., Nature 318:579-582 (1985)); ananther-specific promoter such as that from LAT52 (Twell et al., Mol.Gen. Genetics 217:240-245 (1989)); a pollen-specific promoter such asthat from Zm13 (Guerrero et al., Mol. Gen. Genetics 244:161-168 (1993))or a microspore-preferred promoter such as that from apg (Twell et al.,Sex. Plant Reprod. 6:217-224 (1993)).

Signal Sequences for Targeting Proteins to Subcellular Compartments

Transport of protein produced by transgenes to a subcellular compartmentsuch as the chloroplast, vacuole, peroxisome, glyoxysome, cell wall ormitochondrion or for secretion into the apoplast, is accomplished bymeans of operably linking the nucleotide sequence encoding a signalsequence to the 5′ and/or 3′ region of a gene encoding the protein ofinterest. Targeting sequences at the 5′ and/or 3′ end of the structuralgene may determine, during protein synthesis and processing, where theencoded protein is ultimately compartmentalized.

The presence of a signal sequence directs a polypeptide to either anintracellular organelle or subcellular compartment or for secretion tothe apoplast. Many signal sequences are known in the art. See, forexample, Becker et al., Plant Mol. Biol. 20:49 (1992); Close, P. S.,Master's Thesis, Iowa State University (1993); Knox, C., et al., PlantMol. Biol. 9:3-17 (1987); Lerner et al., Plant Physiol. 91:124-129(1989); Frontes et al., Plant Cell 3:483-496 (1991); Matsuoka et al.,Proc. Natl. Acad. Sci. 88:834 (1991); Gould et al., J. Cell. Biol.108:1657 (1989); Creissen et al., Plant J. 2:129 (1991); Kalderon, etal., Cell 39:499-509 (1984); Steifel, et al., Plant Cell 2:785-793(1990).

Foreign Protein Genes and Agronomic Genes

With transgenic plants according to the present invention, a foreignprotein can be produced in commercial quantities. Thus, techniques forthe selection and propagation of transformed plants, which are wellunderstood in the art, yield a plurality of transgenic plants which areharvested in a conventional manner, and a foreign protein then can beextracted from a tissue of interest or from total biomass. Proteinextraction from plant biomass can be accomplished by known methods whichare discussed, for example, by Heney and On, Anal. Biochem. 114:92-6(1981).

According to a preferred embodiment, the transgenic plant provided forcommercial production of foreign protein is a potato plant. In anotherpreferred embodiment, the biomass of interest is seed or tubers. For therelatively small number of transgenic plants that show higher levels ofexpression, a genetic map can be generated, primarily via conventionalRFLP, PCR and SSR analysis, which identifies the approximate chromosomallocation of the integrated DNA molecule. For exemplary methodologies inthis regard, see Glick and Thompson, Methods in Plant Molecular Biologyand Biotechnology CRC Press, Boca Raton 269:284 (1993). Map informationconcerning chromosomal location is useful for proprietary protection ofa subject transgenic plant. If unauthorized propagation is undertakenand crosses made with other germplasm, the map of the integration regioncan be compared to similar maps for suspect plants, to determine if thelatter have a common parentage with the subject plant. Map comparisonswould involve hybridizations, RFLP, PCR, SSR and sequencing, all ofwhich are conventional techniques.

Likewise, by means of the present invention, agronomic genes can beexpressed in transformed plants. More particularly, plants can begenetically engineered to express various phenotypes of agronomicinterest. Exemplary genes implicated in this regard include, but are notlimited to, those categorized below:

1. Genes that Confer Resistance to Pests or Disease and that Encode:

A. Plant disease resistance genes. Plant defenses are often activated byspecific interaction between the product of a disease resistance gene(R) in the plant and the product of a corresponding avirulence (Avr)gene in the pathogen. A plant variety can be transformed with clonedresistance gene(s) to engineer plants that are resistant to specificpathogen strains. See, for example Jones et al., Science 266:789 (1994)(cloning of the tomato Cf-9 gene for resistance to Cladosporium fulvum);Martin et al., Science 262:1432 (1993) (tomato Pto gene for resistanceto Pseudomonas syringae pv. tomato encodes a protein kinase); Mindrinoset al. Cell 78:1089 (1994) (Arabidopsis RSP2 gene for resistance toPseudomonas syringae).

B. A gene conferring resistance to a pest, such as soybean cystnematode. See e.g., PCT Application WO 96/30517; PCT Application WO93/19181.

C. A Bacillus thuringiensis protein, a derivative thereof or a syntheticpolypeptide modeled thereon. See, for example, Geiser et al., Gene48:109 (1986), who disclose the cloning and nucleotide sequence of a Btδ-endotoxin gene. Moreover, DNA molecules encoding δ-endotoxin genes canbe purchased from American Type Culture Collection, Manassas, Va., forexample, under ATCC Accession Nos. 40098, 67136, 31995 and 31998.

D. A lectin. See, for example, Van Damme et al., Plant Molec. Biol.24:25 (1994), who disclose the nucleotide sequences of several Cliviaminiata mannose-binding lectin genes.

E. A vitamin-binding protein such as avidin. See PCT application US93/06487 which teaches the use of avidin and avidin homologs aslarvicides against insect pests.

F. An enzyme inhibitor, for example, a protease or proteinase inhibitoror an amylase inhibitor. See, for example, Abe et al., J. Biol. Chem.262:16793 (1987) (nucleotide sequence of rice cysteine proteinaseinhibitor), Huub et al., Plant Molec. Biol. 21:985 (1993) (nucleotidesequence of cDNA encoding tobacco proteinase inhibitor I), Sumitani etal., Biosci. Biotech. Biochem. 57:1243 (1993) (nucleotide sequence ofStreptomyces nitrosporeus α-amylase inhibitor) and U.S. Pat. No.5,494,813 (Hepher and Atkinson, issued Feb. 27, 1996).

G. An insect-specific hormone or pheromone such as an ecdysteroid orjuvenile hormone, a variant thereof, a mimetic based thereon, or anantagonist or agonist thereof. See, for example, the disclosure byHammock et al., Nature 344:458 (1990), of baculovirus expression ofcloned juvenile hormone esterase, an inactivator of juvenile hormone.

H. An insect-specific peptide or neuropeptide which, upon expression,disrupts the physiology of the affected pest. For example, see thedisclosures of Regan, J. Biol. Chem. 269:9 (1994) (expression cloningyields DNA coding for insect diuretic hormone receptor), and Pratt etal., Biochem. Biophys. Res. Comm. 163:1243 (1989) (an allostatin isidentified in Diploptera puntata). See also U.S. Pat. No. 5,266,317 toTomalski et al., who disclose genes encoding insect-specific, paralyticneurotoxins.

I. An insect-specific venom produced in nature by a snake, a wasp, etc.For example, see Pang et al., Gene 116:165 (1992), for disclosure ofheterologous expression in plants of a gene coding for a scorpioninsectotoxic peptide.

J. An enzyme responsible for a hyperaccumulation of a monoterpene, asesquiterpene, a steroid, hydroxamic acid, a phenylpropanoid derivativeor another non-protein molecule with insecticidal activity.

K. An enzyme involved in the modification, including thepost-translational modification, of a biologically active molecule; forexample, a glycolytic enzyme, a proteolytic enzyme, a lipolytic enzyme,a nuclease, a cyclase, a transaminase, an esterase, a hydrolase, aphosphatase, a kinase, a phosphorylase, a polymerase, an elastase, achitinase and a glucanase, whether natural or synthetic. See PCTapplication WO 93/02197 (Scott et al.), which discloses the nucleotidesequence of a callase gene. DNA molecules which containchitinase-encoding sequences can be obtained, for example, from the ATCCunder Accession Nos. 39637 and 67152. See also Kramer et al., InsectBiochem. Molec. Biol. 23:691 (1993), who teach the nucleotide sequenceof a cDNA encoding tobacco hornworm chitinase, and Kawalleck et al.,Plant Molec. Biol. 21:673 (1993), who provide the nucleotide sequence ofthe parsley ubi4-2 polyubiquitin gene.

L. A molecule that stimulates signal transduction. For example, see thedisclosure by Botella et al., Plant Molec. Biol. 24:757 (1994), ofnucleotide sequences for mung bean calmodulin cDNA clones, and Griess etal., Plant Physiol. 104:1467 (1994), who provide the nucleotide sequenceof a maize calmodulin cDNA clone.

M. A hydrophobic moment peptide. See PCT application WO 95/16776, whichdiscloses peptide derivatives of Tachyplesin which inhibit fungal plantpathogens, and PCT application WO 95/18855 which teaches syntheticantimicrobial peptides that confer disease resistance.

N. A membrane permease, a channel former or a channel blocker. Forexample, see the disclosure of Jaynes et al., Plant Sci 89:43 (1993), ofheterologous expression of a cecropin-β lytic peptide analog to rendertransgenic tobacco plants resistant to Pseudomonas solanacearum.

O. A viral-invasive protein or a complex toxin derived therefrom. Forexample, the accumulation of viral coat proteins in transformed plantcells imparts resistance to viral infection and/or disease developmenteffected by the virus from which the coat protein gene is derived, aswell as by related viruses. See Beachy et al., Ann. Rev. Phytopathol.28:451 (1990). Coat protein-mediated resistance has been conferred upontransformed plants against alfalfa mosaic virus, cucumber mosaic virusand tobacco mosaic virus.

P. An insect-specific antibody or an immunotoxin derived therefrom.Thus, an antibody targeted to a critical metabolic function in theinsect gut would inactivate an affected enzyme, killing the insect. Cf.Taylor et al., Abstract #497, Seventh Int'l Symposium on MolecularPlant-Microbe Interactions (Edinburgh, Scotland) (1994) (enzymaticinactivation in transgenic tobacco via production of single-chainantibody fragments).

Q. A virus-specific antibody. See, for example, Tavladoraki et al.,Nature 366:469 (1993), who show that transgenic plants expressingrecombinant antibody genes are protected from virus attack.

R. A developmental-arrestive protein produced in nature by a pathogen ora parasite. Thus, fungal endo-α-1,4-D-polygalacturonases facilitatefungal colonization and plant nutrient release by solubilizing plantcell wall homo-α-1,4-D-galacturonase. See Lamb et al., Bio/Technology10:1436 (1992). The cloning and characterization of a gene which encodesa bean endopolygalacturonase-inhibiting protein is described by Toubartet al., Plant J. 2:367 (1992).

S. A developmental-arrestive protein produced in nature by a plant. Forexample, Logemann et al., Bio/Technology 10:305 (1992), have shown thattransgenic plants expressing the barley ribosome-inactivating gene havean increased resistance to fungal disease.

T. Genes involved in the Systemic Acquired Resistance (SAR) Responseand/or the pathogenesis-related genes. Briggs, S. Current Biology, 5(2)(1995).

U. Antifungal genes. See Cornelissen and Melchers, Plant Physiol.,101:709-712 (1993); Parijs et al., Planta 183:258-264 (1991) andBushnell et al., Can. J. of Plant Path. 20(2):137-149 (1998).

V. Genes that confer resistance to Phytophthora blight, such as the R1,R2, R3, R4 and other resistance genes. See, Naess, S. K., et. al.,(2000) Resistance to late blight in Solanum bulbocastanum is mapped tochromosome 8. Theor. Appl. Genet. 101: 697-704 and Li, X., et. al.,(1998) Autotetraploids and genetic mapping using common AFLP markers:the R2 allele conferring resistance to Phytophthora infestans mapped onpotato chromosome 4. Theor. Appl. Genet. 96: 1121-1128.

2. Genes that Confer Resistance to an Herbicide, for Example:

A. An herbicide that inhibits the growing point or meristem, such as animidazolinone or a sulfonylurea. Exemplary genes in this category codefor mutant ALS and AHAS enzyme as described, for example, by Lee et al.,EMBO J. 7:1241 (1988), and Mild et al., Theor. Appl. Genet. 80:449(1990), respectively.

B. Glyphosate (resistance impaired by mutant5-enolpyruvlshikimate-3-phosphate synthase (EPSP) and aroA genes,respectively) and other phosphono compounds such as glufosinate(phosphinothricin acetyl transferase (PAT) and Streptomyceshygroscopicus PAT bar genes), and pyridinoxy or phenoxy proprionic acidsand cyclohexones (ACCase inhibitor-encoding genes). See, for example,U.S. Pat. No. 4,940,835 to Shah, et al., which discloses the nucleotidesequence of a form of EPSP which can confer glyphosate resistance. A DNAmolecule encoding a mutant aroA gene can be obtained under ATCCaccession number 39256, and the nucleotide sequence of the mutant geneis disclosed in U.S. Pat. No. 4,769,061 to Comai. European patentapplication No. 0 333 033 to Kumada et al., and U.S. Pat. No. 4,975,374to Goodman et al., disclose nucleotide sequences of glutamine synthetasegenes which confer resistance to herbicides such as L-phosphinothricin.The nucleotide sequence of a PAT gene is provided in Europeanapplication No. 0 242 246 to Leemans et al. DeGreef et al.,Bio/Technology 7:61 (1989) describe the production of transgenic plantsthat express chimeric bar genes coding for phosphinothricin acetyltransferase activity. Exemplary of genes conferring resistance tophenoxy proprionic acids and cyclohexones, such as sethoxydim andhaloxyfop are the Acc1-S1, Acc1-S2, and Acc2-S3 genes described byMarshall et al., Theor. Appl. Genet. 83:435 (1992).

C. An herbicide that inhibits photosynthesis, such as a triazine (psbAand gs+ genes) or a benzonitrile (nitrilase gene). Przibila et al.,Plant Cell 3:169 (1991), describe the transformation of Chlamydomonaswith plasmids encoding mutant psbA genes. Nucleotide sequences fornitrilase genes are disclosed in U.S. Pat. No. 4,810,648 to Stalker andDNA molecules containing these genes are available under ATCC AccessionNos. 53435, 67441 and 67442. Cloning and expression of DNA coding for aglutathione S-transferase is described by Hayes et al., Biochem. J.285:173 (1992).

D. Acetohydroxy acid synthase, which has been found to make plants thatexpress this enzyme resistant to multiple types of herbicides, has beenintroduced into a variety of plants. See Hattori et al., Mol. Gen.Genet. 246:419, 1995. Other genes that confer tolerance to herbicidesinclude a gene encoding a chimeric protein of rat cytochrome P4507A1 andyeast NADPH-cytochrome P450 oxidoreductase (Shiota et al., PlantPhysiol., 106:17, 1994), genes for glutathione reductase and superoxidedismutase (Aono et al., Plant Cell Physiol. 36:1687, 1995), and genesfor various phosphotransferases (Datta et al., Plant Mol. Biol. 20:619,1992).

E. Protoporphyrinogen oxidase (protox) is necessary for the productionof chlorophyll, which is necessary for all plant survival. The protoxenzyme serves as the target for a variety of herbicidal compounds. Theseherbicides also inhibit growth of all the different species of plantspresent, causing their total destruction. The development of plantscontaining altered protox activity which are resistant to theseherbicides are described in U.S. Pat. Nos. 6,288,306; 6,282,837;5,767,373; and international publication WO 01/12825.

3. Genes that Confer or Contribute to a Value-Added Trait, Such as:

A. Modified fatty acid metabolism, for example, by transforming a plantwith an antisense gene of stearyl-ACP desaturase to increase stearicacid content of the plant. See Knultzon et al., Proc. Natl. Acad. Sci.USA 89:2625 (1992).

B. Decreased phytate content—1) Introduction of a phytase-encoding genewould enhance breakdown of phytate, adding more free phosphate to thetransformed plant. For example, see Van Hartingsveldt et al., Gene127:87 (1993), for a disclosure of the nucleotide sequence of anAspergillus niger phytase gene. 2) A gene could be introduced thatreduced phytate content. In maize, for example, this could beaccomplished by cloning and then reintroducing DNA associated with thesingle allele which is responsible for maize mutants characterized bylow levels of phytic acid. See Raboy et al., Maydica 35:383 (1990).

C. Modified carbohydrate composition effected, for example, bytransforming plants with a gene coding for an enzyme that alters thebranching pattern of starch. See Shiroza et al., J. Bacteriol. 170:810(1988) (nucleotide sequence of Streptococcus mutantsfructosyltransferase gene), Steinmetz et al., Mol. Gen. Genet. 20:220(1985) (nucleotide sequence of Bacillus subtilis levansucrase gene), Penet al., Bio/Technology 10:292 (1992) (production of transgenic plantsthat express Bacillus lichenifonnis α-amylase), Elliot et al., PlantMolec. Biol. 21:515 (1993) (nucleotide sequences of tomato invertasegenes), Søgaard et al., J. Biol. Chem. 268:22480 (1993) (site-directedmutagenesis of barley α-amylase gene), and Fisher et al., Plant Physiol.102:1045 (1993) (maize endosperm starch branching enzyme II).

D. Elevated oleic acid via FAD-2 gene modification and/or decreasedlinolenic acid via FAD-3 gene modification. See U.S. Pat. Nos.6,063,947; 6,323,392; and international publication WO 93/11245.

4. Genes that Control Male Sterility:

A. Introduction of a deacetylase gene under the control of atapetum-specific promoter and with the application of the chemicalN-Ac-PPT. See international publication WO 01/29237.

B. Introduction of various stamen-specific promoters. See internationalpublications WO 92/13956 and WO 92/13957.

C. Introduction of the barnase and the barstar genes. See Paul et al.,Plant Mol. Biol. 19:611-622, 1992).

Methods for Potato Transformation

Numerous methods for plant transformation have been developed includingbiological and physical plant transformation protocols. See, forexample, Miki et al., “Procedures for Introducing Foreign DNA intoPlants” in Methods in Plant Molecular Biology and Biotechnology, Glick,B. R. and Thompson, J. E. Eds. (CRC Press, Inc. Boca Raton, 1993) pages67-88. In addition, expression vectors and in-vitro culture methods forplant cell or tissue transformation and regeneration of plants areavailable. See, for example, Gruber et al., “Vectors for PlantTransformation” in Methods in Plant Molecular Biology and Biotechnology,Glick, B. R. and Thompson, J. E. Eds. (CRC Press, Inc., Boca Raton,1993) pages 89-119.

A. Agrobacterium-mediated Transformation—One method for introducing anexpression vector into plants is based on the natural transformationsystem of Agrobacterium. See, for example, Horsch et al., Science227:1229 (1985). A. tumefaciens and A. rhizogenes are plant pathogenicsoil bacteria which genetically transform plant cells. The Ti and Riplasmids of A. tumefaciens and A. rhizogenes, respectively, carry genesresponsible for genetic transformation of the plant. See, for example,Kado, C. I., Crit. Rev. Plant Sci. 10:1 (1991). Descriptions ofAgrobacterium vector systems and methods for Agrobacterium-mediated genetransfer are provided by Gruber et al., supra, Miki et al., supra andMoloney et al., Plant Cell Reports 8:238 (1989). See also, U.S. Pat. No.5,563,055 (Townsend and Thomas), issued Oct. 8, 1996.

B. Direct Gene Transfer—Several methods of plant transformationcollectively referred to as direct gene transfer have been developed asan alternative to Agrobacterium-mediated transformation. A generallyapplicable method of plant surface of microprojectiles measuring 1 to 4μm. The expression vector is introduced into plant tissues with abiolistic device that accelerates the microprojectiles to speeds of 300to 600 m/s which is sufficient to penetrate plant cell walls andmembranes. Sanford et al., Part. Sci. Technol. 5:27 (1987); Sanford, J.C., Trends Biotech. 6:299 (1988); Klein et al., Bio/Tech. 6:559-563(1988); Sanford, J. C. Physiol Plant 7:206 (1990); Klein et al.,Biotechnology 10:268 (1992). See also U.S. Pat. No. 5,015,580 (Christou,et al.), issued May 14, 1991 and U.S. Pat. No. 5,322,783 (Tomes, etal.), issued Jun. 21, 1994.

Another method for physical delivery of DNA to plants is sonication oftarget cells. Zhang et al., Bio/Technology 9:996 (1991). Alternatively,liposome and spheroplast fusion have been used to introduce expressionvectors into plants. Deshayes et al., EMBO J., 4:2731 (1985); Christouet al., Proc Natl. Acad. Sci. USA 84:3962 (1987). Direct uptake of DNAinto protoplasts using CaCl₂ precipitation, polyvinyl alcohol orpoly-L-ornithine has also been reported. Hain et al., Mol. Gen. Genet.199:161 (1985) and Draper et al., Plant Cell Physiol. 23:451 (1982).Electroporation of protoplasts and whole cells and tissues have alsobeen described. Donn et al., In Abstracts of VIIth InternationalCongress on Plant Cell and Tissue Culture IAPTC, A2-38, p 53 (1990);D'Halluin et al., Plant Cell 4:1495-1505 (1992) and Spencer et al.,Plant Mol. Biol. 24:51-61 (1994).

Following transformation of potato target tissues, expression of theabove-described selectable marker genes allows for preferentialselection of transformed cells, tissues and/or plants, usingregeneration and selection methods well known in the art.

The foregoing methods for transformation would typically be used forproducing a transgenic variety. The transgenic variety could then becrossed with another (non-transformed or transformed) variety in orderto produce a new transgenic variety. Alternatively, a genetic trait thathas been engineered into a particular potato line using the foregoingtransformation techniques could be moved into another line usingtraditional breeding techniques that are well known in the plantbreeding arts.

Persons of ordinary skill in the art will recognize that when the termpotato plant is used in the context of the present invention, this alsoincludes derivative varieties that retain the essential distinguishingcharacteristics of ‘Shelford’, such as a gene converted plant of thatvariety or a transgenic derivative having one or more value-added genesincorporated therein (such as herbicide or pest resistance

Likewise, transgenes can be introduced into the plant using any of avariety of established recombinant methods well-known to persons skilledin the art, such as: Gressel, 1985, Biotechnologically ConferringHerbicide Resistance in Crops: The Present Realities, In Molecular Formand Function of the Plant Genome, L. van Vloten-Doting, (ed.), PlenumPress, New York; Huttner, S. L., et al., 1992, Revising Oversight ofGenetically Modified Plants, Bio/Technology; Klee, H., et al., 1989,Plant Gene Vectors and Genetic Transformation: Plant TransformationSystems Based on the use of Agrobacterium tumefaciens, Cell Culture andSomatic Cell Genetics of Plants; Koncz, C., et al., 1986, The Promoterof T_(L)-DNA Gene 5 Controls the Tissue-Specific Expression of ChimericGenes Carried by a Novel Type of Agrobacterium Binary Vector; Molecularand General Genetics; Lawson, C., et al., 1990, Engineering Resistanceto Mixed Virus Infection in a Commercial Potato Cultivar: Resistance toPotato Virus X and Potato Virus Y in Transgenic Russet Burbank,Bio/Technology; Mitsky, T. A., et al., 1996, Plants Resistant toInfection by PLRV. U.S. Pat. No. 5,510,253; Newell, C. A., et al., 1991,Agrobacterium-Mediated Transformation of Solanum tuberosum L. Cv. RussetBurbank, Plant Cell Reports; Perlak, F. J., et al., 1993, GeneticallyImproved Potatoes: Protection from Damage by Colorado Potato Beetles,Plant Molecular Biology; all of which are incorporated herein byreference for this purpose.

Many traits have been identified that are not regularly selected for inthe development of a new variety but that can be improved bybackcrossing and genetic engineering techniques. These traits may or maynot be transgenic; examples of these traits include but are not limitedto: herbicide resistance; resistance to bacterial, fungal or viraldisease; insect resistance; uniformity or increase in concentration ofstarch and other carbohydrates; enhanced nutritional quality; decreasein tendency of tuber to bruise; and decrease in the rate of starchconversion to sugars. These genes are generally inherited through thenucleus. Several of these traits are described in U.S. Pat. No.5,500,365, U.S. Pat. No. 5,387,756, U.S. Pat. No. 5,789,657, U.S. Pat.No. 5,503,999, U.S. Pat. No. 5,589,612, U.S. Pat. No. 5,510,253, U.S.Pat. No. 5,304,730, U.S. Pat. No. 5,382,429, U.S. Pat. No. 5,503,999,U.S. Pat. No. 5,648,249, U.S. Pat. No. 5,312,912, U.S. Pat. No.5,498,533, U.S. Pat. No. 5,276,268, U.S. Pat. No. 4,900,676, U.S. Pat.No. 5,633,434 and U.S. Pat. No. 4,970,168.

Table 2 shows differences between potato cultivar ‘Shelford’ and potatocultivar ‘Umatilla Russet’. Column one shows a list of characteristicsand columns two and three show the characteristic for ‘ Shelford’ and‘Umatilla Russet’, respectively.

TABLE 2 Potato Variety Characteristic ‘Shelford’ ‘Umatilla Russet’Presence of secondaries Frequent Low on terminal leaflet Color of tuberskin White Russet-colored

DEPOSIT INFORMATION

A tuber deposit of the FRITO-LAY NORTH AMERICA, INC. proprietary POTATOCULTIVAR ‘SHELFORD’ disclosed above and recited in the appended claimshas been made with the American Type Culture Collection (ATCC), 10801University Boulevard, Manassas, Va. 20110. The date of deposit was Jun.27, 2012. The deposit of 25 vials of microtubers was taken from the samedeposit maintained by FRITO-LAY NORTH AMERICA, INC. since prior to thefiling date of this application. All restrictions will be irrevocablyremoved upon granting of a patent, and the deposit is intended to meetall of the requirements of 37 C.F.R. §§1.801-1.809. The ATCC AccessionNumber is PTA-13023. The deposit will be maintained in the depositoryfor a period of thirty years, or five years after the last request, orfor the enforceable life of the patent, whichever is longer, and will bereplaced as necessary during that period.

While a number of exemplary aspects and embodiments have been discussedabove, those of skill in the art will recognize certain modifications,permutations, additions and sub-combinations thereof. It is thereforeintended that the following appended claims and claims hereafterintroduced are interpreted to include all such modifications,permutations, additions and sub-combinations as are within their truespirit and scope.

1. A potato tuber, or a part of a tuber, of potato cultivar ‘Shelford’,wherein a representative sample of said tuber was deposited under ATCCAccession No. PTA-13023.
 2. A potato plant, or a part thereof, producedby growing the tuber, or a part of the tuber, of claim
 1. 3. A potatoplant having all of the physiological and morphological characteristicsof the plant of claim
 2. 4. A tissue culture of cells produced from theplant of claim 2, wherein said cells of the tissue culture are producedfrom a plant part selected from the group consisting protoplast, leaf,stem, root, root tip, anther, pistil, seed, embryo, pollen, ovule,cotyledon, hypocotyl, flower, tuber, eye, tissue, petiole, cell andmeristematic cell.
 5. A potato plant regenerated from the tissue cultureof claim 4, wherein said plant has all of the physiological andmorphological characteristics of the potato cultivar ‘Shelford’.
 6. Amethod for producing a hybrid potato seed comprising crossing the plantof claim 2 with a different potato plant and harvesting the resultanthybrid potato seed.
 7. A method for producing a potato plant thatcontains in its genetic material one or more transgenes, comprisingcrossing the potato plant of claim 2 with either a second plant ofanother potato cultivar which contains a transgene or a transformedpotato plant of potato cultivar ‘Shelford’, so that the genetic materialof the progeny that result from the cross contains the transgene(s)operably linked to a regulatory element.
 8. A method of introducing adesired trait into potato cultivar ‘Shelford’ wherein the methodcomprises: (a) crossing an ‘Shelford’ plant, wherein a representativesample of tubers was deposited under ATCC Accession No. PTA-13023, witha plant of another potato cultivar that comprises a desired trait toproduce progeny plants wherein the desired trait is selected from thegroup consisting of male sterility, herbicide resistance, insectresistance, modified fatty acid metabolism, modified carbohydratemetabolism and resistance to bacterial disease, fungal disease or viraldisease; (b) selecting one or more progeny plants that have the desiredtrait; (c) backcrossing the selected progeny plants with ‘Shelford’plants to produce backcross progeny plants; (d) selecting for backcrossprogeny plants that have the desired trait; and (e) repeating steps (c)and (d) two or more times in succession to produce selected third orhigher backcross progeny plants that comprise the desired trait and allof the physiological and morphological characteristics of potatocultivar ‘Shelford’ listed in Table
 1. 9. A potato plant produced by themethod of claim 8, wherein the plant has the desired trait and all ofthe physiological and morphological characteristics of potato cultivar‘Shelford’ listed in Table
 1. 10. The potato plant of claim 9, whereinthe desired trait is herbicide resistance and the resistance isconferred to an herbicide selected from the group consisting ofimidazolinone, sulfonylurea, glyphosate, glufosinate,L-phosphinothricin, triazine and benzonitrile.
 11. The potato plant ofclaim 9, wherein the desired trait is insect resistance and the insectresistance is conferred by a transgene encoding a Bacillus thuringiensisendotoxin.
 12. The potato plant of claim 9, wherein the desired trait ismodified fatty acid metabolism or modified carbohydrate metabolism andsaid desired trait is conferred by a nucleic acid encoding a proteinselected from the group consisting of fructosyltransferase,levansucrase, α-amylase, invertase and starch branching enzyme or DNAencoding an antisense of stearyl-ACP desaturase.